A fastening structure provided by the present invention is used to fastening a heat dissipating device with a printed circuit board in which a plurality of holes is formed. The fastening structure has a back plate disposed underneath the printed circuit board and a plurality of fitting columns, wherein the back plate is perforated with a plurality of holes and each of the fitting columns has an elongate hollow tube and an insertion member projecting from a periphery of one end of the hollow tube. The hollow tube has a threaded internal sidewall and the insertion member has a shape conformal to the respective holes at which the fitting columns are fixed to the back plate.